off_grid_PV_system

Solar photovoltaic (PV) systems have becoming increasingly widely deployed to provide electricity to remote communities in India and around the world. As an alternative to diesel generation, kerosene lighting or extending the electricity grid network, PV and battery storage can provide power simply and with greatly reduced greenhouse gas emissions when the system is correctly sized.

This work evaluates the effectiveness of mature and emerging PV technologies in meeting the energy demands of rural villages. We have developed a model for finding the most suitable system size based on the technologies chosen, local irradiance data and the requirements of the community that can be applied to a variety of situations. This can help inform policymakers, technology developers and businesses that aim to provide off-­‐grid electricity in the most cost­‐effective manner and with a reduced environmental impact compared to other electrification options.

One study was applied to three locations around India. Four technologies are considered: crystalline silicon, currently the most widely deployed; cadmium telluride, a thin film technology; CPV, which uses highly concentrated sunlight; and organic PV, which in the future could be produced cheaply, efficiently and in high volumes. The model finds the system that has the lowest cost of electricity used by the community over its twenty‐year lifetime.

PV‐generated electricity is found to be able to meet 95% of community demand for   costs   as   little   as   $0.51/kWh   for   cadmium   telluride,   compared   with $0.45/kWh for diesel generation. The specific emissions are as little as 174 gCO2eq/kWh for PV systems, significantly lower than diesel’s 1056 gCO2eq/kWh. PV and storage systems are also more cost‐effective than extending the grid network when communities are greater than 17 km or 25 km from existing infrastructure in plains or mountainous terrain, respectively.

Hybrid systems can use the cheapest combination of PV, battery storage and diesel generation to meet 100% of the electricity demand. At present, the cheapest configuration is dominated by diesel power and has correspondingly high emissions. In the future, however, the expected decreasing cost of lithium‐ion battery storage and increasing price of diesel fuel results in the cheapest hybrid systems featuring more than 80% of their power coming from PV. This transition is expected before 2017 and would have significant implications on the design of off-­‐grid power systems. Further information on this work can be found in a forthcoming research paper.

Philip Sandwell, Ajay Gambhir, Christopher Emmott, Ned Ekins-­‐Daukes and Jenny Nelson